1 /*
2 * Copyright (c) 2022, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 *
7 * This code is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 only, as
9 * published by the Free Software Foundation.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 #include "precompiled.hpp"
28 #include "memory/allocation.hpp"
29 #include "oops/markWord.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "runtime/globals.hpp"
32 #include "runtime/lockStack.inline.hpp"
33 #include "runtime/objectMonitor.inline.hpp"
34 #include "runtime/safepoint.hpp"
35 #include "runtime/stackWatermark.hpp"
36 #include "runtime/stackWatermarkSet.inline.hpp"
37 #include "runtime/thread.hpp"
38 #include "utilities/copy.hpp"
39 #include "utilities/debug.hpp"
40 #include "utilities/globalDefinitions.hpp"
41 #include "utilities/growableArray.hpp"
42 #include "utilities/ostream.hpp"
43
44 #include <type_traits>
45
46 const int LockStack::lock_stack_offset = in_bytes(JavaThread::lock_stack_offset());
47 const int LockStack::lock_stack_top_offset = in_bytes(JavaThread::lock_stack_top_offset());
48 const int LockStack::lock_stack_base_offset = in_bytes(JavaThread::lock_stack_base_offset());
49
50 LockStack::LockStack(JavaThread* jt) :
51 _top(lock_stack_base_offset), _base() {
52 // Make sure the layout of the object is compatible with the emitted code's assumptions.
53 STATIC_ASSERT(sizeof(_bad_oop_sentinel) == oopSize);
54 STATIC_ASSERT(sizeof(_base[0]) == oopSize);
55 STATIC_ASSERT(std::is_standard_layout<LockStack>::value);
56 STATIC_ASSERT(offsetof(LockStack, _bad_oop_sentinel) == offsetof(LockStack, _base) - oopSize);
57 #ifdef ASSERT
58 for (int i = 0; i < CAPACITY; i++) {
59 _base[i] = nullptr;
60 }
61 #endif
62 }
63
64 uint32_t LockStack::start_offset() {
65 int offset = lock_stack_base_offset;
66 assert(offset > 0, "must be positive offset");
67 return static_cast<uint32_t>(offset);
68 }
69
70 uint32_t LockStack::end_offset() {
71 int offset = lock_stack_base_offset + CAPACITY * oopSize;
72 assert(offset > 0, "must be positive offset");
73 return static_cast<uint32_t>(offset);
74 }
75
76 #ifndef PRODUCT
77 void LockStack::verify(const char* msg) const {
78 assert(LockingMode == LM_LIGHTWEIGHT, "never use lock-stack when light weight locking is disabled");
79 assert((_top <= end_offset()), "lockstack overflow: _top %d end_offset %d", _top, end_offset());
80 assert((_top >= start_offset()), "lockstack underflow: _top %d start_offset %d", _top, start_offset());
81 if (SafepointSynchronize::is_at_safepoint() || (Thread::current()->is_Java_thread() && is_owning_thread())) {
82 int top = to_index(_top);
83 for (int i = 0; i < top; i++) {
84 assert(_base[i] != nullptr, "no zapped before top");
85 if (VM_Version::supports_recursive_lightweight_locking()) {
86 oop o = _base[i];
87 for (; i < top - 1; i++) {
88 // Consecutive entries may be the same
89 if (_base[i + 1] != o) {
90 break;
91 }
92 }
93 }
94
95 for (int j = i + 1; j < top; j++) {
96 assert(_base[i] != _base[j], "entries must be unique: %s", msg);
97 }
98 }
99 for (int i = top; i < CAPACITY; i++) {
100 assert(_base[i] == nullptr, "only zapped entries after top: i: %d, top: %d, entry: " PTR_FORMAT, i, top, p2i(_base[i]));
101 }
102 }
103 }
104 #endif
105
106 void LockStack::print_on(outputStream* st) {
107 for (int i = to_index(_top); (--i) >= 0;) {
108 st->print("LockStack[%d]: ", i);
109 oop o = _base[i];
110 if (oopDesc::is_oop(o)) {
111 o->print_on(st);
112 } else {
113 st->print_cr("not an oop: " PTR_FORMAT, p2i(o));
114 }
115 }
116 }